I've come up with quite the strange idea in my daily brainstorm/daydream sessions.

It's a fantasy-like game, but based in a post-apocalyptic world.

The earth is flooded from extreme volcanic activity in the Antarctic. Modern human civilization has basically been forgotten.

This is when dragons come onto the scene. I haven't worked out how yet...maybe they are found underground like reign of fire?

These aren't your typical dumb dragons from other stories, these dragons are a advanced telepathic species with technologies eons beyond mankind.

Instead of conquering the humans the use their ability to control human minds to basically sit back and relax and have human kings and queens build up civilizations for the sole purpose of supporting the wealth of their dragon overlords.

Now gameplay is where things become interesting. Players have a dragon for an in game avatar. Dragons are really hard to kill, but they are not immortal. When your dragon dies it is lost forever (permadeath).

When I say hard to kill, I mean it literally. Probably the only way to kill a dragon will be by using another dragon- even then you will have advanced technologies as well as a human army ready to die for you.

Players may play as their dragon, but typically they will mind-control a human for most tasks.

These humans are bred, bought, or enslaved and must be trained over time (think eve-online style training).

Humans die permanently. However, because you can acquire as many as you can afford to feed its not a big loss.

Some aspects of the game will feel slightly RTS-like. Instead of floating in the clouds and looking down, you will mind-control a human and walk among your people dispatching commands in a more hands-on way.

Multiple dragons may rule one human empire (this is like the guild/clan concept). Dragons have telepathy so there will be an in-game world chat as well as your typical guild and tell chat channels.

This is very rough, but what do you think?

There's not a lot of flesh on your concept yet. Your core concept seems to be a master-minion relationshipment. The master (dragon, necromancer, alien) has control over one or more minions (humans, zombies). So, do you play the master or do you play the minion or both ?

Most tradional MMO(RPG) have an avatar, which the player shapes, get bound to. This could get somewhat difficulty if you only have an exchangable minion most of the time. Think about pet-based classes in MMORPGs (wow -hunter, guild wars necro etc.), do you ever feel linked to the pet ?

It depends on how you implement the relationship. Eg in overlord you control the master and minions, in more traditional RTS games you most often only control the minions, so I don't really see in which direction your game/gameplay is going.

But the basic idea about a master-minion relationshipment sounds quite interesting.

So, do you play the master or do you play the minion or both ?

Both.

While you can run around and cause havoc as your dragon, the species is limited.

Dragons are not very good at mining or farming or manufacturing because of their physical limitations.

The human minions have AI and follow the orders of their human leader who is influenced by the dragons.

Most human minions will just follow their AI and perform tasks like farming, mining, etc that players may not wish to perform themselves.

Players will control their select few of chosen human minions to go out and do things that they enjoy doing manually (like pvp or world exploration).

Think about pet-based classes in MMORPGs (wow -hunter, guild wars necro etc.), do you ever feel linked to the pet ?

Its not really a pet. When you control your human, you are in that persons body and you move around as that person. Your dragon will most likely be hidden somewhere safe (wherever you were when you switched to mind control) to avoid being attacked. Your dragon could be on the other side of the world from your human.

You can almost think of it as a complex spin on the character selection screen.

You have to build training facilities and allocate some feasible number of humans to training. The remaining human population will be busy manning industry and agriculture.

It depends on how you implement the relationship. Eg in overlord you control the master and minions, in more traditional RTS games you most often only control the minions, so I don't really see in which direction your game/gameplay is going.

The dragons can be used in the game world, but because of permanent death it is quite risky to fly around consuming every human you find in the wilderness or to treat the next city you find as an all-you-can-eat buffet.

Through controlling humans, dragons are able to build empires to defeat other dragons (and to hoard gold in the process of course).